Thin TiCx films chemically vapour deposited onto cemented carbides from the TiCl4-CCl4-H-2 mixture

Results on the study of the deposition rate, structure, composition and some properties of TiCx films deposited from the TiCl4-CCl4H2 gaseous mixture when varying the CCl4/TiCl4 mole ratio are presented. The crystal lattice parameter of the films slightly increases when increasing the CCl4/TiCl4 ratio from 0.3 to 0.8. The average grain size of the TiCx films significantly decreases and their microhardness correspondingly increases when decreasing the CCl4/TiCl4 ratio from 0.5 to 0.1. The deposition rate has a maximum at the CCl4/TiCl4 ratio value of around 0.4. Due to enhanced reactivity of CCl4 compared with that of methane utilized as a carbon source in the CVD of TiCx films, it is possible to completely eliminate formation of a decarburized eta-phase underlayer in the cemented carbide substrate when depositing from the TiCl4-CCl4-H-2 mixture. The TiCx films when applied as wear-resistant coatings for cemented carbide tools allow improvement in tool lifetime comparable with that of conventional TiCx coatings chemically vapour deposited from the TiCl4-CH4-H-2 mixture.